|Pollutant|Units|Emission Standard|Coal-fired|Petroleum Coke-fired|
|---|---|---|---|---|
|SO2|lb/MMBTU|≤ 0.15|0.0−0.04|0.03−0.13|
|NOx|lb/MMBTU|≤ 0.09|0.04−0.06|0.02|
|Solid particulate|lb/MMBTU|≤ 0.011|0.004|0.007|
|PM10|lb/MMBTU|≤ 0.011|0.006|0.004|
|SO3|lb/hour|≤ 1.1|0.43|0.0|
|Fluoride|lb/MMBTU|≤ 1.57×10−4|1.06×10−4|0.95×10−4|
|Lead|lb/MMBTU|≤ 2.6×10−5|0.56×10−5|0.59×10−5|
|Mercury|lb/MMBTU|≤ 1.05×10−5|0.095×10−5|0.028×10−5|

Question: what is the total number of pollutants that are measured with an lb/mmbtu unit?
Answer: 7